Arc lamp



Feb. 27, 1934. 5.0. LIGHTNER ARC LAMP Original Fil'ed March 15, 1930 2 Sheets-Sheet 1 nveni'or'.

gefze hiner,

Augie.

Feb. 27, 1934. 1,948,669

ARC LAMP Originl Filed March 13, 1930 2 Sheets-Sheet 2 .Patented Feb. 27., 1934 ABC LAMP 7 Eugene O. Lightner, Washington, D. 0.

Application March 13,

1930, Serial No. 435,492

Renewed February 24, 1933 33 Claims.

My present invention relates to improvements in arc lamps, and more particularly it relates to improvements in high intensity reflecting arc lamps and is designed for accessibility and Simplicity and to increase efilciency and economy in operation.

An object of the invention is to materially reduce the obstruction of light by the positive carbon feeding mechanism and to locate substantially all such rotating and feeding mechanism so as not to be affected by the are heat.

Another object is the provision of holding means for the positive carbon free from massive structure and free from mechanism readily afifected by heat such as ratchets, cams, rollers, and

pawls, such holding means being capable of withstanding the heat close to the arc and thus capable of holding a short positive carbon in proper position, which materially reduces the carbon loss which heretofore has been very great as it has been necessary to throw away up to onethird of the positive electrode due to the location of the actuating mechanism at a considerable distance away from the arc to prevent injury to 2| same by the heat.

A further object is to increase the useful life of the positive carbon jaws many times over the designs in use heretofore by the provision of means whereby the positive electrode is only pushed through the positive jaws and is not revolved within them thereby reducing friction, and by providing means whereby the jaws are rotated which serves to prevent overheating of any particular portion of the jaws and which causes the II heat to be uniformly distributed against and evenly radiated from the baffle.

A further object is the provision of means for effecting instantaneous changing or replacement of the positive electrode while the arc is in use,

a and allowing the positive carbon to be used up to a point determined only by the limit of proximity to the arc of a highly refractory metal shield forthe positive carbon and by the area of electrical contact between the holding means and u the electrode necessary to properly conduct the desired amperage.

Other objects will appear hereinafter.

The invention consists in the features, combiw nation, and arrangement of, parts hereinafter described and particularly pointed out in the claims.

In the drawinss Figure 1 is a side elevation of the apparatus constituting an embodiment of my invention.

Fig. 2 is a front elevation partly in section on line 2-2 at Fig. 1 looking in the direction of the arrows.

Fig. 3 is an enlarged longitudinal section on line 3-3 of Fig. 2, parts being broken away.

Fig. 4 is an enlarged detail sectional view of 69 a part 01' the drive gearing and gearshiiting mechanism in a different position of adjustment from that shown in Fig 1.

Fig. 5 is a view of the gear shifting yoke and gear.

. Fig. 6 is an enlarged sectional view of the electrodes and the holding means for the positive electrode.

Fig. 7 is a perspective view of one of the gripping jaws for the positive electrode.

Fig. 8 is an enlarged view of the positive carbon carrier and ejector in gripping position.

Fig. 9 is a section on line 9-9 of Fig. 2 showing the-positive holding ring in its trough shaped guideway. j 7

In the drawings, 1 represents the positive carbon or electrode of my high intensity reflecting arc lamp and 2 is the negative electrode while 3' represents the motor which through slow drive gearing, automatically feeds the electrodes as they are consumed in the arc. The reflector is shown at 4 which reflects the light 'from the arc and throws it forwardly through and beyond the holding means for positive electrode 1. The refiector may be supported by any suitable means.

The positive electrode is supported at its arc end as shown in Figs. 1, 2, and 6, by gripping jaws 5 having nodules 6 thereon for snapping into removable engagement between spring arms 7 secured to the inner periphery of the rotary supporting ring 8 and extending radially inward, the arms 7 having openings 9 therein to receive the nodules 6. The jaws are adapted to grip the electrode and to hold it centrally of the supporting ring 8. Current is conducted from the ring through the spring arms and jaws to the electrode.

Also secured to the ring and extending inwardly therefrom between the spring arms is a bracket arm 10 having a backing or abutment plate 11 secured thereto for preventing movement or strain upon the jaws as the electrode is retracted therethrough for removal in case it is defective requiring replacement or trimming", or where it is retracted in adjustment of the arc.

The rotary supporting ring 8 has its outer periphery bearing in a semi-circular trough 12 formed at the top of the gear housing and base 13, the base being secured to the floor or base 14 of the lamp housing by bolts 15 and insulated therefrom by suitable insulation 16.

The rotary ring 8 is provided along one edge of its outer peripheral surface with gear teeth 17 meshing with spur gear 18 having a bearing on pin 19 mounted in the housing 13. The spur gear 18 is provided with a smaller gear portion 20 adapted to mesh with shiftable gear 21 which forms a part of shiftable sleeve 22 splined to feed screw shaft 23 at 24. The sleeve 22 as shown is preferably made in two parts interlocked at 25 but this is for purposes of assembly andfthe operation is the same as if it were made in one piece.

The outer end of the sleeve 22 is provided with a spur gear 26, the outer portion of said gear being beveled as shown at 2'7. The gear is normally pressed into engagement with the teeth of bevel gear 28 of drive shaft 29 by means of spring 30 pressing against the opposite end of the sleeve 22 and a collar 31 fixed on the feed screw shaft 23. With this construction when the shaft 23 and the sleeve 22 splined thereto, are rotated, the

' spring will rotate with them and there will be 1 no tendency to relative rotation against an end of the spring.

The drive shaft 29 at its end opposite to the bevel gear 28 is provided with a worm gear connection 32 to the shaft 33 of a suitable motor 3. This provides for slow rotation of the bevel gear 28 and consequent slow rotation of the-feed screw shaft 23.

With the bevel portion 2'? of gear 26 pressed by spring 38 into mesh with drive gear 28 the feed screw shaft 23 is rotated which rotates the splined sleeve 22 and the gear 21 in mesh with gear 20. The rotary positive electrode holding ring is thus rotated through gear 18 engaging peripheral teeth; 17 on the ring.

At the same time the feed screw shaft 23 extending forwardly beyond the housing 13 and having a bearing at its forward end in support 35, is longitudinally screw threaded as shown at 36 and is in threaded engagement with electrode feeder or carrier 37 to move the same toward the are as the screw 23 is rotated by the motor. Insulation 34 is provided between the support and the base 14 of the lamp housing. The insulation may be of fibre or other suitable material which will not conduct electric current.

Positive electrode gripping and ejecting means are rotatably mounted in the upper end of the carrier 37, to grip the electrode and to rotate therewith. This construction will be more particularly described hereinafter. The gripping means rotates with the carrier and the carrier moves the electrode toward the are when driven by the motor One or more guide rods 26 may be provided for the carrier 3'2, the carrier having corresponding guide openings 97 for sliding on said rods.

Means for discormecting the screw shaft 23 from the motor and for operating the screw 23 manually, are provided. A longitudinally shiftable shaft 38 is mounted for rotation in suitable bearing support 39, and in the housing 13.

The shaft 38 is provided with a hand crank or wheel ll and a gear 42 fixed to the shaft and adapted to be shifted into or out of operative engagement with the gear 26. Supported freely upon the shaft 38 is a yoke member 43 having a collar portion 44 through which the shaft passes, the yoke member extending into a slot 45 in the sleeve 22.

In the operation of this part of the apparatus,

it will be apparent that by pushing upon the handle or crank 41, the shaft 38 will be moved longitudinally from the position shown in Fig. 1 to that shown in Fig. 4, the gear 42 being moved into mesh with the gear 26 and into engagement with the yoke 43 thus moving the yoke and sleeve 22 as a unit away from the gear 28 thus disconnecting the gear 27 from the gear 28. This same movement or" the sleeve also disconnects the gear 21 from the gear 20as shown in Fig. 4. With the parts in the position shown in Fig. 4 with the shaft 38 pushed in, the shaft 38 may be manually rotated in either direction to rotate screw shaft 23 and to move the carrier 37 toward or away from the are as desired. At the same time the manual effort is reduced by the disconnection of the gripping ring operating gearing. The gear ratio for manual operation is preferably such that a rotation or a partial rotation of the hand control crank 41 will move the carrier 37 sever'al inches along the screw 23.

This hand control for manually positioning .the carrier 37 and for positioning the positive electrode is also adapted upon pulling the hand wheel 41, to similarly disconnect the negative 1B0 electrode feed gearing from the drive gear 28. A yoke 46 on the opposite side of gear 42 engages in slot 47 in gear 48 which is splined to rotary shaft 49. The gear 48 has bevel gear portion 51 to mesh with drive gear 28.

The shaft 49 has supporting hearings in supports 39 and 40 and is provided with bevel gear 50 fixed thereto.

The bevel gear 50 meshes with bevel gear 52 on negative feed screw 53 which is mounted in inclined bracket 54 fastened to support 48. The negative electrode 2 at its forward end passes through a guide opening in flange 56 of bracket 54 and at its rear end is supported negative feed carrier 57 threaded upon screw 53. A return spring 58 surrounds the shaft 49 and is disposed between the collar 59 fixed to the shaft 49 and the slidable gear 48 to urge the gear toward drive gear 28. The shaft, collar, spring and gear all rotate as a unit so that there is no rotation of the spring bearing surfaces relative to the spring. Thus means are provided for manually positioning either the positive or the negative electrode. Preferably, the slidable gear shifting shaft 38 is provided with circumferential grooves indicating positive electrode control position at 60, neutral position at 51, and ne ative electrode control position at 62, with respect to a snap ball as within the support 39.

It will be apparent from the construction as thus far described, that with the gears inlthe position as shown in 1 both the positive and negative electrodes will be fed to the arc with the positive electrode rotating and the gripping ring therefor providing holding means close to the are light, free from mechanical parts such as ratchets, gears, earns, rollers, and pawls which would be afiected by the heat, and free from any light obstructing mass, the ring permitting the reflected light to pass therethrough. with full and unobstructed intensity.

As the gripping jaws rotate with the ring and so rotate the positive electrode which they hold between them, there is no relative rotation be tween the electrode and the jaws, and the sliding movement of the electrode as it is fed through the jaws is the only rubbing or wearing to which the jaws and electrode are subjected.

In Fig. 8 the positive electrode gripping and ejecting means are shown in grippinr position. 50

a guide opening 64 in which is slidably mounted a jaw housing 65. An extension 66 at the top of the carrier 37 provides a bearing opening '67 through which extends a rod 68 provided with a collar 69 and shouldered and reduced at 70 to prevent longitudinal movement relative to the carrier while permitting rotation of the rod. The

,rod 68 has a head and its shank 68 extends through an opening '73 in partition or wall 74 in the housing 65. The shank 68 extends through the wall '74 and through spring well or bore 75 in which a coil spring 76 is disposed surrounding said shank and bearing at one end against wall "14 and at its other end against a collar 77 fixed to the shank. The shank beyond the collar 7'7 extends to its bearing'6'1 in extension 66 and is held therein'by collar 69. It will be apparent from this construction that the jaw housing 65 can be pushed to the right from the position the head 71 coming between them, for either the ejection of the carbon or the insertion of a fresh carbon as in Fig. 1. Three jaws '18 are shown but any suitable number may be provided. Moving the housing toward the bearing 6'7 causes it 0 to pass over the pawl 80 pivoted in a slot 81 in the upper guide face of the carrier, and the weight of the pawl will cause it to swing its head 82 into the peripheral groove 83 in the end of the jaw housing to lock orretain it in retracted position with the jaws open, until the pawl is manually tripped as by tapping it to the left, as with the pair of pliers usually used in inserting a new electrode. When the pawl 80 is tripped the housing will move ,to the left to the gripping position shown in Fig. 8 under action of the spring. t I

Rotation of the positive electrode 1 by revolving holder 8 also rotates the gripping jaws '18, the jaw housing 65, the rod 68 and the spring 76 all as a unit, so that there is no relative rotation between the spring and the surfaces against which its ends bear. 7

With the arc in operation and the jaws in the carrier in the gripping position shown in Fig.

5c 8 the positive electrode is gradually fed to the are under power of the screw 23 driven through thegearing by the electric motor 3. When the end 84 of the jaw housing 65 engages the spring gripping jaws 5 with all but a very small portion of the positive electrode having been .con-

' sumed, the continued feeding of the carrier causes the housing to be pushed all the way back on the carrier and against the abutment 66a with its end 84 flush with the corresponding at; end of the carrier 37. This releases the jaws and ejects the old positive electrode from the gripping jaws '78. The old positive electrode then occupies the position in which it is shown in Fig. 6 with the head '71 hearing against it after having 55 pushed it to the position shown in Fig. 6.

At this point the carrier has been moved toward the are as far as it will go, determined by the end of the threads on the screw" 23 having been reached and by the front of the carrier 0 abutting the gear housing 13. At this point also the housing 65 has been fully retracted to such position that it has passed over and beyond pawl and is in position to return to be locked by the head of the pawl 82 engaging groove 83 and '35 holding the housing in "trimming" or new car the carrier with the spring jaws.

bon inserting position upon the carrier 37 being withdrawn.

The hand control 41 is next actuated by pushing it to disconnect the motor 3 and to connect the hand control with the screw 23 for manual operation all as hereinbefore described.

The screw 23 is then rotated in the opposite direction by the hand control 41 through the multiplying gearing so that a partial turn of the hand wheel 41 retracts thecarrier 37 several inches along the screw 23, and it is moved to position beyond the length of a fresh positive carbon as shown in Fig. 1. The jaw housing during the retracting movement occupies the locked position shown in Fig. 1 with the jaws open in readiness to receive the new electrode. The fresh positive electrode is inserted as shown in Figs. 1 and 6 with its arcing end abutting the old electrode within the jaws 5 and its opposite end within the jaws 78. The pawl lever 80 is then tripped to release the lock and the jaw housing moves under action of the spring 76 causing the frictional sliding engagement of the jaws 78 with the head 71 to urge the jaws together to securely grip the electrode. The electrode being thus securely gripped enables it to be readily withdrawn from connection with the jaws of the holding ring by retraction of the carrier in case of emergency such as the electrode being defective and requiring "trimming or replacement before it has been substantially consumed and before the car-. rier has reached ejecting position.

The apparatus is then in position to feed automatically upon return of the hand control to neutral position with the screw 23 driven by the motor.

From the above description of the apparatus and operation it will be seen that the new electrode is inserted in a minimum of time in a simple and effective manner without stopping the are light which continues to burn uninterruptedly.

In Figs. 1 and 6 is shown a battle or shield 85 of highly refractory heat resistant metal secured to the arm 10 and covering the jaws 5, the baffle being provided with an aperture 86 for the passage of the positive electrode and serving as a stop to prevent strain on the spring arms and jaws as the electrode is pushed therethrough and during the ejection engagement of The shield is preferably curved away from the jaws 5 as shown to provide a heat insulating air space, and incidentally providing a second point of support enabling the old positive stub to be used up until its end has reached a. point about midway of the bore of the jaws when it may be pushed out by the new positive as by quick manipulation of the hand control 41 to properly position the new electrode, so that in the hands of a skilled operator no break will occur in the arc. The electric circuit is established as shown diagrammatically in Fig. 1.. A flat spring brush 8'7 is secured to the gearing housing 13 as shown at 88 and bears upon the inner periphery of the revolving positive electrode holding ring 8 to ensure an eifective electric contact, although some of the electric current may and will pass directly through the housing 13 through trough 12 into the ring asit revolves in the guide or trough 12. The circuit is completed from the line through the double throw switch 89, through wire 90 to the gear housing at connection 91, through the gear housing, brush 87, ring 8, jaws. 5, positive electrode 1, the arc, negative elecibo , to the line.

trode 2, carrier 57, wire 92 to the switch and back The motor is connected in parallel with the are by means of wires 93 and 94 tapped in on leads and 92. A rheostat 95 is preferably inserted in the motor circuit as shown. The negative electrode bracket 54 is insulated at 97 at its connection to the support 40 and the bevel gears 52 and 50 are of fibre or other insulation to thoroughly insulate the negative electrode, and its bracket and carrier from the remainder of the apparatus.

The negative electrode is preferably coated with copper and is about 8 inches in length while the positive electrode in such case would be about 20 inches inlength.

It will be apparent from the foregoing that by my invention as illustrated in the embodiment shown and described, great economy and efficiency in operation is attained, the carbon loss being reduced one-half to three-quarters of the loss heretofore. The increase in the life of the positive jaws by my construction and the immediate changing of the positive electrode while the arc is in use also are material advantageous features.

I do not desire to limit my invention to the exact construction shown as many modifications may be made within the scope of my invention as defined in the appended claims.

In the top of the carrier 37 is preferably provided an opening 98 for the admission of oil to the housing bearing.

I claim:

1. In an arc lamp 8. current feeding holder for an electrode mounted on a rotating current feeding member having an opening therein through which the light from the arc is projected.

2. In an arc lamp, a current feeding holder for an electrode secured to a rotary current feeding ring through which the light from the arc is projected.

3. In a reflecting arc lamp, a current feeding holder for an electrode secured to a rotary current feeding ring through which the reflected light from the arc is projected.

4. A high intensity reflecting arc lamp including a current feeding electrode holder secured to a rotary current feeding ring through which the reflected light from the arc is projected, said electrode being held within the said rotary ring and rotating therewith.

5. In an arc lamp, means for rotating an electrode, said means rotating in an entirety and as a unit with said electrode, said means having an opening therein for the passage of the light from the are without itself obstructing the light, said electrode being held by said means within said opening.

6. In an arc lamp according to claim 5 said means comprising a rotor ring having jaws extending inwardly from its periphery to hold the electrode within the ring, drive gearing engaging gear teeth on the outer periphery of said ring to rotate the ring about a horizontal axis, means for feeding electric current into the rotor, said current passing from the rotor ring into the jaws and from the jaws into the electrode.

7. In an arc lamp, jaws for holding the positive electrode of said lamp and for feeding electric current thereto, a rotary ring for supporting the jaws and electrode, said ring providing for the passage of the light therethrough, means for maintaining axial alignment of said electrode including a baffle plate secured adjacent the jaws and supported by the ring, said baflle plate having an opening therein for the passage of said electrode and said baffle plate shielding said jaws from the direct heat of the arc, said electrode, jaws, baflie plate, and ring being rotatable as a unit, said baiile plate bracing said jaws against movement toward the arc.

8. In an arc lamp, holding means for an electrode of said lamp, said holding means rotating said electrode, means for feeding said electrode through said holding means, said feeding means including an electrode gripping, aligning and ejecting carrier operable upon engagement with said holding means to eject the electrode from said carrier into said holder, said carrier being adapted to receive one end of a new electrode and to cause the other end to engage the end of the old electrode to feed the same toward the arc and to eventually force it from the holder and replace it when it is substantially all consumed, all without interruption to the continuous operation of the arc.

9. An arc lamp according to claim 8 in which said holding means includes a baille plate disposed at the side nearest the arc, said banie plate being of refractory material and having an opening therein for passage of said electrode to align and support theelectrode, means for feeding current through said holding means to the electrode, said baffle plate of said holding means being so disposed that the electrode may be used up almost entirely and to a point determined only by the limit of proximity of the arc to the refractory battle and by the area of electrical contact between the holding means and the electrode necessary to properly conduct the desired amperage.

10. An arc lamp including an electrode gripping, aligning and ejecting carrier operated by a slow feed screw, said carrier having a horizontal bore in its upper portion, a cylindrical jaw housing slidably disposed in said-bore, a rod rotatably secured at one end in said carrier against longitudinal movement, said rod extending through said housing and having an ejector enlargement at its free end, said housing having a bore and a partition with an opening through which the rod extends, said rod enlargement being disposed in the far side of the partition fromits connection to the carrier, a spring abutment collar on said rod between the partition and the connection to the carrier and receivable in the housing bore, a coil spring surrounding said rod and bearing against said partition and said abutment collar,

electrode gripping jaws pivotally mounted in slots in the walls of the housing beyond said partition 7.

and said abutment collar, electrode gripping jaws pivotally mounted in slots in the walls of the. housing beyond said partition and operable by engagement with said rod enlargement to swing into and out of the bore forming the electrode receiving socket to grip or release the electrode, said spring pressing said housing partition against the enlargement and urging said housing to gripping position, said housing and rod rotating together, said housing being depressible against the action of the spring to open the jaws over the ejector enlargement.

11. An arc lamp including a screw operated electrode gripping carrier having a jaw housing horizontally slidable and rotatable therein, a spring for urging the housing outwardly to gripping position, jaws pivoted in slots within the mouth of the housing, a stop on said carrier for limiting the outward movement of said housing,

said stop cooperating with said jaws to operate 150 said feed screw" shaft extending through said' the same upon relative movement between the housing and carrier.

12. An arc lamp according to claim 11 in which said housing is provided with a circumferential groove in its outer surface and a pawl with a handle pivoted in said carrier and adapted to swing into said groove to lock the housing in electrode replacement position. v

13. An arc lamp according to claim 11 in which said stop is rotatable in said carrier and in which said jaws, stop, housing and spring rotate together with the electrode.

14. In an arc lamp, a rotary ring having Jaws for holding an electrode centrally thereof, an arcuate bearing support for the rim of saidring, said ring having peripheral gear teeth, a housing supporting said arcuate bearing, a feed screw shaft for moving said electrode through the Jaws,

housing, a sleeve splined to said feed screw shaft and movable longitudinally thereon, a gear on said sleeve within the housing, peripheral teeth on the ring, multiplying gearing between said sleeve gear and peripheralteeth, a second gear on said sleeve adapted at the same time to be driven by asuitable motor and through the sleeve to drive the first mentioned gear and ring, spring means for urging said sleeve to. so engage said gears, a rotary gear shifting and operating shaft extending into said housing, said gear shifting shaft beng longitudinally movable, a gear on said shiftable shaft, a yoke engaging said sleeve and hung on said shiftable shaft and adapted to be moved by said gear on said shaft when the shaft is shifted, said yoke moving the sleeve to disconnect the motor from said second gear, said shifting of the shaft moving its gear into mesh with the said second gear so that the rotation of the shiftable shaft will drive the feed screw shaft, said shifting of the sleeve disconnecting the ring gearing from the first mentioned gear.

15. An arc lamp including a feed screw shaft for feeding a positive electrode, means for holding said positive electrode and means on the feed screw shaft to drive said holding means together with the electrode.

16. An arc lamp according to claim 15 including a feed screw operating shaft for a negative elec-.

trode, sleeves splined one to each shaft and slidable thereon, gears on said sleeve driven by a common motor, springs urging the sleeves to connect the gears with the motor, a rotary shiftable shaft, a gear on the shiftableshaft adapted when the shaft is shifted to mesh with either of said gears, yokes hung on said shiftable shaft and engaging said gear sleeves, said yokes being adapted upon shifting of the shaft and its gear into mesh with one of said sleeve gears to be engaged by said gear to move the sleeve gear out of connection with the motor for positioning said electrodes by rotation of the shiftable shaft.

1'7. An arc lamp according to claim 15 in which is provided a feed carrier for the positive electrode, said feed carrier being operated by said feed screw, said feed carrier having a retractible electrode gripping jaw housing with a fixed ejector within the housing, said carrier upon engagement of the :law housing with the said holding means causing retraction of said housing and ejection of said electrode from the housing and carrier into the holding means, and means for immediately and rapidly withdrawing said carrier for insertion of a fresh positive electrode in said carrier and in said holding means to form a continuation of said old electrode without interruption of the are light.

18. An arc lamp including means for holding and rotating an electrode at its arc end, carrier means for supporting said electrode at its opposite end and for feeding, it toward said are and through said holding means, said carrier means being adapted to move against said holding means and to eject the remnant of the electrode from the carrier means into the holding means with room for the insertion of an end of a fresh electrode to form a continuation of said renmant, said carrier means being adapted to be immediately withdrawn to receive the opposite end of the fresh electrode, so that the arc light will be unaffected by the supplying of the new electrode.

19. An arc lamp according to claim 18 in which said holding and rotating means for said electrode includes an upright ring not obstructing the light but through which the light is to pass, said ring having peripheral teeth, means for rotating said ring by said teeth, a pair of spring arms extending inwardly from said ring, a pair of electrode holding jaws snapped between said arms and adapted to support the electrode centrally .of the ring opening, and means secured to said ring and bracing said Jaws against movement longitudinally of the electrode.

20. In arc lamp apparatus, a ring-shaped member through which the light is projected, having means carried thereby for holding a carbon with its axis coinciding with the axis of said ring, and means for rotating said ring to thereby rotate the carbon about its axis, the light rays from the are passing through theopening of said ring, the major portion of the space within the ring being unobstructed for the passage of the light rays.

21. In apparatus according to claim 20, in which said holder for said carbon extends from said ring radially thereof to the center of said ring, the space within the ring along the opposite radius and to each side of the radii being free.

22. In apparatus according to claim 20, a reflector for reflecting light rays through the opening within thering. i

23. Apparatus according to claim 20, in which a channeled, arcuate shaped housing supports and guides the ring, said ring having exterior gear teeth-by which power is transmitted to the ring for rotating the same.

24. Apparatus according'to claim 20, in which the interior of the ring is free for the passage of the light excepting for the presence of the carbon holding means carrier by said ring.

25. In combination in arc lamp apparatus, a rotatable ring through the opening of which the light rays from the arc pass, means carried by the ring for holding a carbon at the center of the ring coaxially therewith, means for feeding the carbon through the holder carried by the ring, said feeding means'having an ejector to deposit the carbonin said holder upon the arresting of said feeding means by contact with the carbon holding means of the ring, substantially as described.

26. Apparatus according to claim 25, in which said feeding means includes a member revolubly supported to rotate with the carbon, said means being yieldingly held in a forward position by a Ill spring, detent means for retaining said member 2?. In an arc lamp, a rotating ring through which the light from the arc is projected, means for supporting and rotating said ring, and a current conducting holder for the electrode at the axial center of the ring, said electrode being held coaxially with the ring, substantially as described.

28. In an arc lamp apparatus, a rotating ring shaped member through which the light is projected having means for holding one end of a carbon with its axis at the center of the ring, a second member for aligning the other end of the carbon in the axis of the rotating ring member and means for moving one member relative to the other to adjust the distance between them to compensate for shortening of the carbon due to burning.

29. Apparatus according to claim 28, in which one of said members is also a current feeding member for the carbon.

30. In an arc lamp apparatus, a rotating ring shaped member through which the light is projected having means for holding one end of a carbon with its axis at the center of the ring and a second member for aligning the other end of the carbon in the axis 01 the ring member, the member at the end of the carbon opposite to that at which the arc occurs being movable toward the other member to feed the carbon through said other member.

31. In an arc lamp apparatus, a rotating ring shaped member through which the light is projected having means for holding one end oi a carbon with its axis at the center of said ring member, and a second member for aligning the other end of the carbon in the axis of the ring member, the member at the end of the carbon at which the arc occurs being at a fixed distance from the arc and the other member being movable toward said fixed member to feed the carbon through said fixed member.

32. In an arc lamp, a rotatable ring through which light from the 'arc is projected, said ring having means for holding a carbon with its axis 

